Martina Jackson, cochairwoman of the Newton Democratic City Committee, showed Joseph P. Kennedy III around Newton South High School, where the candidate attended a Democratic caucus and met residents a few days before announcing his candidacy.

Joseph Kennedy III officially launched his campaign for Congress in February, greeting commuters and supporters in Newton.

In this January 2010 photo, former Massachusetts Rep. Joseph P. Kennedy II, left, hugs his son, Joseph P. Kennedy III, after introducing him during a campaign event for the Senate candidacy of Martha Coakley.

After graduating in 1999 from Buckingham, Browne & Nichols, where they were cocaptains of the football team, Joe and Matt Kennedy attended Stanford University.

Joe branched out after graduating and worked in the Peace Corps in the Dominican Republic. He joined his brother as campaign manager of Ted Kennedy’s reelection campaign in the spring of 2006.

Kennedy spent two years in the Dominican Republic, where he helped to organize an eco-tourism project.

Joseph Kennedy III, wearing white shirt in front row, along with members of the BB&N Spanish Club.

A photo in the Buckingham, Browne, and Nichols yearbook had the caption: ‘‘Mom—Thanks for everything! I don’t think I would have made it without you.’’

A campaign event, with (from left) Max Kennedy, Ethel Kennedy, Matt, Joe III, Joe Kennedy II, Suzanne Knight, Phil Johnston.